This invention relates to a thermostatic valve for controlling the temperature of the coolant of an internal-combustion engine, particularly of a motor vehicle engine. The invention relates particularly to a thermostatic valve which has a working piston, a piston supporting body which can be adjusted by means of an adjusting element, and an elastic restoring device which restores the working piston away from the supporting body.
In the case of a known thermostatic valve of the initially mentioned type disclosed in German Patent Document DE-C 35 04 653, an electric motor is provided as the adjusting element which adjusts a supporting body constructed as an eccentric. The elastic restoring device for the working piston of the thermostatic valve is supported on this working piston and on the valve housing in such a manner that it presses the working piston when the coolant temperature falls back into its inoperative position. This ensures that there are no undesirable operating conditions of the thermostatic valve and thus of the internal-combustion engine.
It is also known from German Patent Document DE-A 32 26 104 to provide as the supporting body a piston of a thermostatic working element which is aligned coaxially with the working piston of the thermostatic valve.
It is an object of the invention to provide a construction of a thermostatic valve of the initially mentioned type that is as simple as possible.
This object is achieved in that the supporting body is a piston of a thermostatic working element which is aligned coaxially with respect to the working piston, and in that the restoring device is supported against the working piston and against the piston of the thermostatic working element.
By using a thermostatic working element as the adjusting element and its piston as the supporting body, a simplification of the construction is achieved. By means of the special arrangement of the restoring device, it is additionally achieved that the working piston as well as the piston of the thermostatic working element are each restored into their initial positions when the coolant temperature and temperature to which the thermostatic working element is exposed. The restoring is therefore achieved by means of only one restoring device so that the construction is simplified further. By means of this restoring device, it is ensured that undesirable operating conditions of the internal-combustion engine are avoided which are the result of undesirable working positions of the thermostatic valve.
In a further development of the invention, it is provided that a transmission element is arranged between the piston of the thermostatic working element and the working piston, which transmission element presets an idle path and transmits pressure forces. A transmission element of this type offers further possibilities for simplifying the construction.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.